There are three levels of truth about the 9/11 attack on the United States:
1) What the public has been told, mostly for the benefit of the US government,
2) What the government officials, functionaries, and administrators have been told, and
3) What really happened.
The first two are mostly lies. Not surprisingly, any attempt to explain what happened from collections containing lies will never neatly add up.
Dimitri Khalezov was an officer of the Soviet military charged with the responsibility of handling data concerning nuclear weapons. In this capacity, certain information became known to him, which in his assessment, makes what happened on 9/11 very clear indeed.
All of it will likely be challenging, even to the seasoned 9/11 investigator. At the same time, all of it is very rewarding. I do not think anyone may consider themselves well versed in the subject without giving him a full hearing.
Please remember that Mr. Khalezov only considers himself an expert witness on the particular subject of nuclear weapons and how they are used. He is also an eyewitness to certain personalities involved. The rest of it he considers merely a well informed and considered opinion.
Included here is a second PDF, which contains a smaller book by the same author comparing events of Chernobyl reactor disaster and the 9/11 disaster.